Effects of inertance on respiratory mechanics measurements in mechanically ventilated children.
Pediatr Crit Care Med
; 9(1): 80-5, 2008 Jan.
Article
de En
| MEDLINE
| ID: mdl-18477918
ABSTRACT
OBJECTIVE:
The use of the first-order linear single compartment model when studying respiratory mechanics classically neglects inertance (Irs). We hypothesized that Irs would affect compliance (Crs) and resistance (Rrs) estimates in mechanically ventilated young children.DESIGN:
Prospective study; single-center evaluation.SETTING:
University-affiliated tertiary pediatric intensive care unit. PATIENTS Forty-four patients with and without respiratory disease.INTERVENTIONS:
Patients were studied during volume-controlled constant inspiratory flow ventilation. MEASUREMENTS AND MAINRESULTS:
Pressure (PaO) and flow (V') were analyzed according to two different models a one-compartment first-order linear model according to PaO = (1/Crs) x V + Rrs x V' and a one-compartment second-order linear model according to PaO = (1/Crs) x V + Rrs x V' + Irs x V''. Irs was higher in children with vs. those without respiratory disease (median 0.00224 cm H2O/L/sec2, Q1-Q3 0.00180-0.00321 vs. median 0.00133 cm H2O/L/sec2, Q1-Q3 0.00072-0.00210; p < .001)). A positive correlation between Irs and the difference of Crs estimates between the first- and the second-order model was found in both groups (r = .84, p < .05 and r = .67, p < .05). Rrs estimates were similar in both groups.CONCLUSIONS:
This study showed that the linear single-compartment model may not adequately estimate the respiratory mechanical properties in mechanically ventilated children, particularly in the presence of respiratory disease. Including an Irs term significantly diminished Crs estimates. A one-compartment second-order linear model might be a useful clinical tool in more adequately measuring respiratory mechanics and optimizing ventilatory settings in children with respiratory disease.
Texte intégral:
1
Collection:
01-internacional
Base de données:
MEDLINE
Sujet principal:
Ventilation artificielle
/
Mécanique respiratoire
/
Compliance pulmonaire
/
Modèles statistiques
Type d'étude:
Observational_studies
/
Risk_factors_studies
Limites:
Humans
/
Infant
Langue:
En
Journal:
Pediatr Crit Care Med
Sujet du journal:
PEDIATRIA
/
TERAPIA INTENSIVA
Année:
2008
Type de document:
Article
Pays d'affiliation:
France